From the episode "Prototype" (which was one of the better season 9 eps, btw)
Holding hands while helping Cameron up...

Followed by incredibly gay hand movement from Cameron...

And then actual arm-stroking.

Poor Jack, if he only knew. The worst thing is that it is all his fault: if Daniel hadn't fallen in love with Jack all those years ago, he wouldn't have that thing about military men with guns now. And if Jack wasn't so incredibly in love with Daniel, Daniel would never have discovered his alpha-male side the way he did. So how can he resist when Cameron insists that he needs some extra training with the P-90 and then stands so close to Daniel on the shooting range, so close that he can feel the heat from his body, Cam's breath like a gentle touch on his neck?
How can he stop himself from being turned on when they walk up the range together, shooting in synchronicity? And instead of asking him if he is okay afterwards, making him think and feel, like Jack would di it, Cameron just looks at him later, in the locker room, looks at him as if he can't believe that he really is the lucky guy who gets to shoot people with Dr. Daniel Jackson, gets to share the locker room with him. Looks at him as if he would drop down to his knees right then and there if Daniel asked him to, the risk of bing discovered just making him want it more.
For a moment, Daniel is tempted to ask, but he can't do that to Jack, who always resisted the temptation and insanity of doing it in the locker room, no matter how much they both wanted it. But can you blame Daniel for taking Cameron home after that, watching him wander around his house, looking at the pictures of SG-1, the original, the only SG-1, unable to believe that he gets to be part of that now.
Sometimes, Washington is far far away. And after days like this, maybe it is too far away.
Poor Jack. My heart breaks with yours.